1. Field of the Invention
This invention relates to the preparation of methacrylamide by reacting methylmethacrylate with a large molar excess of aqueous ammonium hydroxide in the temperature range of about 10.degree. C. to about 40.degree. C. More particularly, the process of the present invention provides a high yield high product quality methacrylamide which is readily isolated from the other reaction products and compatible in the preparation of isocyanate resins.
2. Description of the Prior Art
Methacrylamide is utilized in the preparation of isocyanate resins used in the formulation of paints and other coating compositions. The methacrylamide heretofore employed in such resinous compositions has generally been purchased from foreign sources that produce the methacrylamide by utilizing a high temperature process. Methacrylamide produced by this process is of acceptable purity in isocyanate resins but the cost of producing methacrylamide by these high temperature processes accounts for the high cost of this compound. Methacrylamide products have also been produced by other processes involving catalysts and variations of temperatures and processes using various feed stocks. However, the prior art processes heretofore available have generally required expensive equipment, elaborate separation equipment and techniques to separate the methacrylamide produced from the other by-products.
Another type of process such as the one disclosed in U.S. Pat. No. 2,451,436 prepares methacrylamide by reacting an amine with methylmethacrylate. The reaction conditions employed are rather harsh and as a result of elevated temperatures various by-products are produced which either require expensive separation techniques or result in a reaction product that is not compatible with the preparation of isocyanate resins.
The use of methacrylamide in isocyanate resin and resinous containing compositions such as paints and coating compositions has created a demand for high purity methacrylamide that can be produced in high yields at commercially attractive prices. The process for the production of methacrylamide should additionally employ inexpensive feedstocks and be an uncomplicated process providing a high yield high purity methacrylamide in which any by-products produced by the process should be fully compatible with the use of methacrylamide with isocyanate resinous compositions. Furthermore, a commercially attractive process should further allow the easy isolation of methacrylamide from any by-products produced in addition to a high selectivity for the production of the methacrylamide with corresponding high production yields.